Thank you Mistamontiel for the save file. I tried to modified something in the file BASLUS-20595SETTINGS, but it didn't work it was still Amaterasu nickname on screen. I manage to create a profile but at the end just after it asks for your birth date, it says it can't connect to game spy and so it won't allow you to use this new profile to play online. I saw on my memory card that another folder was created it is called "BASLUS-20595A5100000". In this folder there are 3 files : BASLUS-20595A5100001 , gray.icn and icon.sys . I think the account informations are stored in the BASLUS-20595A5100001 file so amaterasu confirmed profile is in the file BASLUS-20595A5100000.

I opened it with Hxd a hexadecimal editor but couldn't find anything revealant. I will keep searching. I will compare those 2 files BASLUS-20595A5100000 and BASLUS-20595A5100001. The difference should be : different nickname, different birth date, confirmation of the profile and different online avatar, and may be different controller configuration. I will let you know.